Table 1. Photophysical data of complexes 1–4.

Complex	Medium pH a	λ ex/λem b	Φ c	Φ Δ d
1	3.0	405/523, 551	0.077	0.42
	5.0	405/523, 574	0.051	0.24
	6.5	405/523, 577	0.035	0.15
	7.4	405/523, 578	0.024	0.07
2	3.0	405/576	0.092	0.51
	5.0	405/557, 590	0.060	0.29
	6.5	405/557, 598	0.039	0.17
	7.4	405/557, 598	0.019	0.05
3	3.0	405/512, 547	0.063	0.31
	5.0	405/512, 548	0.034	0.14
	6.5	405/513, 548	0.022	0.09
	7.4	405/514, 549	0.014	0.04
4	3.0	405/527, 576	0.026	0.20
	5.0	405/526, 587	0.013	0.11
	6.5	405/525, 588	0.010	0.07
	7.4	405/525, 588	0.008	0.03

^aDisodium hydrogen phosphate–citric acid buffer solutions.

^bExcitation wavelengths (λ_ex) and maximum wavelengths of emission spectra (λ_em) in nm.

^cThe emission quantum yields at room temperature were determined using [Ru(bpy)₃]Cl₂ in aerated H₂O (Φ = 0.028)19 as the reference.

^dThe Φ_Δ were determined using [Ru(bpy)₃]Cl₂ in aerated H₂O (Φ_Δ = 0.18)18 as the reference.